Blading.



J. E. SNYDER.

BLADING.

APPLICATION FILED M AR. 21, 1912.

L?5,@?. Patented 0015.14, 191s.

NVENTOF?.

@Y TMM /S ATTORNEY /N FACT.

H51' E. SNYDER, 0F STNESSVALE, PENNSYLVANEA, ASSIGNQR TO THE WNESTTNGHQUSE MAClN-ll COMEANY, CQB/FQRATJN F PENNSYLVANA.

BLADNG.

imacat Application tiled March 21, 1912,

To ZM wim/1i t may concern,

Be it known that l, JOHN F. SNrDnP., a citizen of the `United States, and a resident of taivissvalo, in the county ot Allegheny and State of Pennsylvania. have made a new and uset'ul Invention in Blading, of which the following is a specification.

This invention relates to turbine bladesl and means for fastening tlieln to a bladeholding element.

One of the objects of my invention is to provide a turbine blade wl ich will resisty the vibrations due to high rotative speed ot' the rotor to which they are attached.

Another object of the invention is to provide ineans whereby the blades may be rig;- idly secured to the blade-holding element.

Another object o the invention is 'to provide a blade, the longitudinal cross-sectional area oi" one part ot which will be consider ably greater than the remaining portion of the blade.

Other objects and advantages ot the `invention Will be specil'ically described hereinafter, it being understood that changes in 'foi-In, proportion, and ininor details ot con struction may be resorted to Wit-hout departing from the spirit ot the invention or sacriticing any ot its advantages.

In the drawings: Figure 1 is a longitudinal sectional view through a rotor constructed in accordance with my invention. Fig. 2 is a cross-sectional view on the line 2--2 of Fig. 1. Fig. 3 is a longitudinal sectional view through one of the blades. Fig. Li is a cross-sectional view through one of the blades; and Fig. 5 is a detail perspective view of ono of the packing pieces.

Referring now to the drawings by numerals of reference7 1() designates a blade-holding,- element which may consist. of a rotor oli a turbine. The blade-landing element is illustrated` as beinev provided with. a groove 11 having under-cut port-ions l2 and 125. in the surface of the groove 'i1 is a subjaccnt groovev lllthe width of which is less than the Width of' the groove 11. rille grooves 11 and 1li are designed tor the purpose ol `re ceivin;, the roots ot blades 15 ot which there will be a suitable nuinber to comprise a ring', the individual bladis beingspaced apart, by the packing pieces 16.

The detail'construction oi'f the blades is best shown in Fig. 3 in which a single blade is illustrated as conijiisiuY a body portion Specication of Letters atent.

. Patented @ein il el? if Serial o. 685,225.

which is concavo-convex and the erossssectional area of which is symmetrical for a considerable length of the blade as indicated at l?. 'ihe root end of the blade. however, is thickened for a portion o1A s length sufficient to enable the thickened portion 18 to extend beyond the surface olf the blade-holding element to which the blade is s cured. ln actual practice it has been found that the blades usually break or become ruptured at approximately the point where 'they leave the blade-holding element andv y i have round that by thiclninini;A the blade tor a distance 'from the root end suiiiciently to carry the thickened portion beyond the surface ot the blade-holding; element, the blade made rigid and is less liable to vibrate or become disrupted. "lliis is in 'part due to the :tact hat the moment of inertia of the blade is ntreased beyond the surface of 'the bladeiolding element, so that the blade is strengthened at the point of greatest stress, and the vibrations are absorbed tliroughout the entire blade length instead of at approximately ora point as is connnon in blades nou' generally employed. The bottom portions or roots oi' tl ne blades are prowhich are of approximately the width of the groove ifi but ot less width than the groove 11. An act zal practice the blades may be introduced into the groove 11 so that the projections 19 will rest. in the groove lll. The packing' pieces 16 may also be placed iu the groove 11 so that the bottoni' tace oi' each packing piece will rest upon the upper tace ot a projection 1E) ot an adjacent: blade, it being understood that the blades and packing' pieces are alternately introduced into the `groove 11. The. packing piece 1b' here illustrated is shown as beingl provided with an inclined face QU and a straighti'aee 21. The inclined tace the aching piece 16 will be inserted into the` und/veut portion i2 ot' the groove 11, the straight tace 21 being spaced troni but: adjacent` to the under-cut portion 13 of the groove 11, fitter the blades and packing; pieces are in. place they may be rigidly heid by inserting conugound wedges 22 which may be rallied in place' in the usual manner.

llaviugr thus deseril'ied iuyinrxention, l claiin is:

1. it turbine blade comprising a body portion, a considerable length of which is symwhat vided with right-angular projections 19.

metrical in shape and the root portion of which is thickened for a length of the blade suicient to permit a part of the thickened portion to extend beyond the surface of the blade-holding element when the blade is in place, and a projection at the root end of the blade which extends at right angles to the body portion of the blade.

2. A turbine blade comprising a body p01'- tion, a considerable length of which is symmetrical in shape and the root portion of which is thickened for a length of the blade sufficient to permit a part of the thickened portion to extend beyond the surface of the blade-holding element When the blade is in place, and a projection at the root end of the blade which extends at right angles to the body portion of the blade, said projecting portion being of less Width. than the Width of the blade.

3. In combination with a blade-holding element having a groove therein, blades in the groove and packing pieces between the blades, each blade comprising a relatively thick root portion extending beyond the packing pieces, the rest of the blade being of uniform thickness from the thickened portion to the end of the blade and of less thickness than the root of the blade.

In testimony whereof, I have hereunto subscribed my name this 19th day of March,

JOHN E. SNYDER. Witnesses:

C. W. MCGHEE,

ANNA CLOHERTY. 

